$(function(){
    $("#su").hover(function(){
        $("title").html("hover");
    },function(){
        $("title").html("leave");
    });
});
chrome.extension.onMessage.addListener(function(message, sender, sendResponse){
    console.log("contentScript get a message");
    if(message.from == "background.js"){
        console.log("I am content.js, I receive a massage from background.js, that is: " + message.message);
        sendResponse(
            {
                message: "hello, good evening.",
                from: "this is from content.js"
            }
        );
    }
});
console.log("inContentJs");
